F Accessibility Support

Contents

F.1 WAI Accessibility Guidelines

This appendix explains how accessibility guidelines
published by W3C's Web Accessibility Initiative (WAI) apply to
SVG.

The "Web Content Accessibility Guidelines 1.0" [WCAG]
explains how authors can create Web content that is
accessible to people with disabilities.

The "Authoring Tool Accessibility Guidelines 1.0" [ATAG] explains how
developers can design accessible authoring tools such as SVG
authoring tools. To conform to the
SVG specification, an SVG authoring tool must conform to
ATAG (priority 1). SVG support for element grouping, reuse and navigation is relevant to
designing accessible SVG authoring tools.

The "User Agent Accessibility Guidelines 1.0" [UAAG] explains how
developers can design accessible user agents such as
SVG-enabled browsers. To conform to the SVG specification, an
SVG user agent must conform to to the Priority 1 accessibility
guidelines defined in[UAAG] , and should conform also to Priorities 2
and 3.UAAG. SVG support for
scaling, the DOM, and metadata are all relevant
to designing accessible SVG user agents.

The W3C Note "Accessibility Features of SVG" [SVG-ACCESS]
explains in detail how the requirements of the three guidelines
apply to SVG.

F.2 SVG Content Accessibility Guidelines

This section explains briefly how authors can create
accessible SVG documents; it summarizes and builds upon "Accessibility Features
of SVG" [SVG-ACCESS].

When the text content of a graphic (e.g., in a 'text' element) explains
its function, no text equivalent is required. Use the 'title' child element to
explain the function 'text' elements whose
meaning is not clear from their text content.

When a graphic does not include explanatory text
content, it requires a text equivalent. If the equivalent
is complex, use the 'desc' element, otherwise
use the 'title' child
element.

If a graphic is built from meaningful parts, build
the description from meaningful parts.

Do not rely on color alone.

Do not use color alone to convey semantic information.

Ensure adequate color contrast.

Use markup correctly.

Separate structure from presentation.

Use the 'g' element and rich
descriptions to structure SVG documents. Reuse named
objects.

Publish highly-structured documents, not just
graphical representations. Documents that are rich in
structure may be rendered graphically, as speech, or as
Braille. For example, express mathematical relationships
in MathML [MATHML] and use
SVG for explanatory graphics.

Author documents that validate to the SVG
RelaxNG grammar.

Use text for text, and graphics for graphics

Represent text as character data, not as glyphs, images or
curves.

Style text with fonts. Authors may describe their
own fonts in SVG.

Do not use 'pi' fonts or picture fonts to represent small graphics. The
resulting garbage text does not conform to [CHARMOD] and confuses text to
speech engines.

Provide a default reading order

Use 'textArea' elements to provide
text that wraps in a box, rather than using script to wrap the text or
using a sequence of unrelated 'text' elements.

Clarify natural language
usage.

Use xml:lang to identify the
natural language of content and changes in natural
language. This ensures that textual content can be spell-checked,
or converted to speech.

Do not assume that all devices have a pointer device. Allow for keyboard navigation as well.

Provide links for 8-way directional navigation.

Ensure that dynamic content is
accessible.

Ensure that text equivalents for dynamic content are
updated when the dynamic content changes.

Avoid storing dynamic text in ecmascript arrays or in XSLT stylesheets.
This makes it less accessible, and also increases the difficulty of localising
the text or providing multilingual alternatives.

Ensure that SVG documents are still usable when scripts or
other programmatic objects are turned off or not
supported.

F.3 SVG User Agent Accessibility Guidelines

This section explains how implementors of SVG User Agents can make their software
more accessible.

Provide access to color information

SVG User Agents should implement and document APIs so that assistive
technologies can have access to color information on individual elements.

SVG User Agents should provide an optional high contrast view.

Provide a text-only view

SVG user Agents should provide mechanisms that allow assistive
technologies to achieve a useful text-only view. Examples include a DOM explorer,
a synchronized text only view, or an XSLT style sheet to convert the textual
content to XHTML.

Allow for rich navigation

Provide links for 8-way directional navigation.

Allow multimodal navigation and interaction

SVG user Agents should provide access to zooming and panning through
modalities other than a pointer device, if available

SVG user Agents should allow animations, audio, and video to be started,
stopped and paused using modalities other than a pointer device, if available.

Allow keyboard navigation

Where a keyboard is supported, it should be possible to us it to zoom and pan, as well
as start, stop, and pause animations, audio, and video.